1. What is Bazett's Formula?

Bazett's formula is a widely used method for correcting the QT interval for heart rate. The corrected QT interval (QTc) helps assess cardiac repolarization and identify potential arrhythmia risks, particularly in clinical settings.

2. How Does the Calculator Work?

The calculator uses Bazett's formula:

Where:

• \( QT \) — Measured QT interval from start of Q wave to end of T wave (ms)
• \( RR \) — RR interval = 60 / HR (seconds)
• \( HR \) — Heart rate (beats per minute)

Explanation: The formula adjusts the QT interval for heart rate variations, providing a standardized measure of ventricular repolarization.

3. Importance of QTc Calculation

Details: Accurate QTc calculation is essential for diagnosing long QT syndrome, monitoring drug effects on cardiac repolarization, and assessing arrhythmia risk in various clinical conditions.

4. Using the Calculator

Tips: Enter QT interval in milliseconds and heart rate in beats per minute. Both values must be positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal QTc value?
A: Normal QTc values are typically <440 ms for men and <460 ms for women. Values above these thresholds may indicate prolonged QT syndrome.

Q2: Why use Bazett's formula specifically?
A: Bazett's formula is one of the most commonly used corrections in clinical practice due to its simplicity and widespread validation, though it may overcorrect at high heart rates.

Q3: When should QTc be measured?
A: QTc should be measured in patients taking medications that affect cardiac repolarization, those with syncope or family history of sudden death, and in routine ECG interpretations.

Q4: Are there limitations to Bazett's formula?
A: Yes, it tends to overcorrect at high heart rates and undercorrect at low heart rates. Other formulas (Fridericia, Hodges) may be used in specific situations.

Q5: How is the RR interval calculated?
A: RR interval (in seconds) is calculated as 60 divided by the heart rate (in beats per minute).